The daytime outside temperature was in the 80s every day and 40s to 50s at night, probably warmer inside the car which was parked in the sun at times for hikes and meals. The cooler was opened 4 or 5 times a day for food and drinks.
The cooler was the new Coleman 32-qt. "EXTREME." It sells for $29.95 at most sporting goods stores. We got ours at Sports Authority on Sunset Blvd, Henderson, NV., in the Mall just past Sunset Station Casino. We found that, like most plastic coolers, it's very hard to clean. The motion of cans, etc. causes black marks that are almost impossible to remove. Also, the desert dust was hard to remove from the outside. However, we highly recommend this cooler for extended trips.